Suppression of polarization effect in deep-ultraviolet light-emitting diodes with composition-graded triangle electron-blocking layer

Impacts of polarization effect and electron-blocking layer (EBL) on the characteristics of deep-ultraviolet (DUV) light-emitting diode (LED) are investigated numerically. Simulation results show that the DUV LED with a bulk AlGaN EBL of high aluminum composition possesses good capability of electron confinement in general, while the characteristics deteriorate dramatically when the degree of polarization is high. Instead, the DUV LED with a composition-graded triangle AlGaN EBL is found to be less sensitive to the variation of polarization effect and possesses su-perior output performance in comparison with the counterpart LED with a bulk AlGaN EBL under high degree of polarization. The composition-graded triangle AlGaN EBL is beneficial for the DUV LED with high crystalline quality due to the relatively slight energy band deformation under high degree of polarization.